You'll notice that you can sort based on things like release date and Metacritic score. And you can use the little search function to do things like search for keywords (e.g., LEGO) or to only show games with a metascore above 70, for example.

There are also links to the Metascore page and the Steam page for each game (when they're available).

Anyway, you'll figure it out.

My wife and I are always looking for new local coop & multiplayer games, so if you find anymore let me know and I'll add them to the site.

My wife and I are always looking for good local coop or local multiplayer games that we can play together on our living room HTPC. Steam has a list of games that fall into this category, but it is far from complete. Anyway, for those of you that are interested, I've compiled a more comprehensive list of local coop/multiplayer games (games which allow either 2 players to play simultaneously on the same screen, or have a split screen mode).

Left 4 Dead 1 & 2 (yes, I know it's a hack, but it works)Trine (of course, as mentioned by others. This is one of the best local coop games out there).The Undergarden (Superb new local coop game! My wife and I absolutely love playing this game together). Shatter (This needs to be on the Steam coop list...great fun with 2 controllers). Terminator Salvation (I know this game didn't receive great reviews, but it's actually a lot of fun in split screen mode)Watchmen: The End is Nigh (Another one that didn't get great reviews, but is a great beat-em-up in split screen)Watchmen: The End is Nigh 2 (Don't actually own it yet, but apparently this has split screen as well)Swarm ArenaVirtual Tennis 2009 (Not really a local coop; perhaps a "local VS" would be a more appropriate moniker. Play tennis against your buddy or significant other...like Pong with good graphics. Super fun)Street Fighter IV (Again, more of a "local VS" game, but let's not split hairs. I would actually love to see more PC games where you can play AGAINST someone on the same PC. It goes without saying, with two 360 controllers, it's a lot of fun to beat on your friends in the same room, on the same PC...the way video games were meant to be played!). Shrek Forever After (Don't actually own it, and not sure if I'd admit it if I did. Tempted to purchase though just because of local coop). Dungeon Defenders (Coming Soon to an HTPC near you).Serious SAM (the old ones) (I don't actually own any of these, but I know the older ones had 4 player split screen...too bad the new ones don't)Overlord IOverlord II (Just bought it and randomly discovered it had a split screen mode).Magnetis (Just bought this one as well. It has a split screen "VS" mode that we've played a few times...good stuff!)Flight Control HD (Technically, not a local coop game...but if you have 2 input devices...in our case 2 gyration motion remotes, you can guide the little airplanes to safety together...it's hilarious when you're both struggling to save different planes).Shadowgrounds & Shadowgrounds Survivor (purchased survivor, but haven't got local coop to work yet). ProtoGalaxyAudiosurfBionic Commando: Rearmed Star Wars Clone Wars: Republic HeroesMagicka Blue Toad Murder Files™: The Mysteries of Little Riddle

Now for some racing games that have split screen mode:

BlurCrash Time IITOCA Race Driver 3Split/Second (Ok, not on Steam, don't actually own it, but supposed to be good)Sonic and SEGA All STAR Racing

Unreal Tournament 3 has a split screen hack, like l4d (haven't used it myself).BlazBlue Calamity Trigger - 2 player vs (only available on Games for Windows Live in the US)Worms Reloaded- up to 4 players, you take turns making moves.Trackmania - local vs, but not at the same time; you take turns trying to beat each other's score. tracks are tiny, though, so there's not much waiting around.Gumboy Tournament - never played it, not sure what it's like

Gamersgate has a lot of small/indie/import titles, some of which have coop etc.:SwitchfireAcceleration of SUGURI

A few harder to find titles:Sega Rally Revo: 2 player racing split screenX-Men Legends II: Rise of Apocalypse (I think...)Guilty Gear & Melty Blood series (fighting games, only released in japan but you can find guilty gear at least on amazon)Dynasty Warriors 4 and 6 (again, imports afaik)

And I'm pretty sure some free indie games have co-op as well, like.. Streets of Rage Remake
Super Mario War
and Super Smash Land

Helpful list, been looking for local co-op games recently and learned something...

...Developers need to realize that it's not only console users that want split screen co-op........

Agreed completely. What's really frustrating is that they actually remove the split screen mode when they port some console games to the PC (e.g., Kane & Lynch 2), or make it difficult to access (L4D). With monitors getting larger, and more and more people gaming on HTPCs on large flatscreen TVs in their living room, the demand for more local coop (split screen) games on the PC is just going to increase; developers need to take note of this.

Yeah, co-optimus is actually the main site I referred to when trying to find local coop games. Thanks for the post though. I wish Steam had similar searching capabilities (e.g., filter by split screen).